1. Field of the Invention
The present invention relates to a roof-installed object securing device for securing a roof-installed object to be installed on roof, such as a solar cell module, onto a roof structural member.
2. Description of the Related Art
The present applicant has proposed the following supporting tile as a securing device for securing a roof-installed object (for example, solar cell module, solar water heater, roof-installed greening body) to be installed on roof onto a roof structural member such as roofboard and rafter (Japanese Patent No. 3450123). The supporting tile includes a tile main body which is formed to have a shape substantially the same as a roof member (roof tile) thatched on the roof structural member and is mounted on the roof structural member and a supporting projection projecting upward from the upper surface center portion of the tile main body, and the roof-installed object is secured onto the supporting projection.
However, in the technique as disclosed in Japanese Patent No. 3450123), the weight of the roof-installed object acts on the supporting tile overall, so that the supporting tile is formed with a metal having high strength and rigidity for enduring the weight thereof. Due to this, there is room for improvement in that the cost required for the supporting tile (securing device) is increased.
On the other hand, the following securing device has been proposed (Japanese Patent Application Laid-open No. 2004-278110). The securing device includes a cover member that is installed on a roof structural member and is formed to have a shape substantially the same as a roof member and on which a rectangular through-hole is formed and a supporting member that is inserted into the through-hole of the cover member and is mounted on the roof structural member. A roof-installed object is secured onto the upper surface of the supporting member on the securing device. In the technique as disclosed in Japanese Patent Application Laid-open No. 2004-278110, the supporting member onto which the roof-installed object is secured is mounted on the roof structural member through the through-hole of the cover member, so that the weight of the roof-installed object does not act on the cover member. This makes it possible to use a material having low strength and rigidity at the relatively reduced cost for the cover member, thereby reducing the cost required for the securing device.
However, in the technique as disclosed in Japanese Patent Application Laid-open No. 2004-278110, the supporting member onto which the roof-installed object is secured is formed to have a U shape by bending a flat plat-like member and is mounted on the roof structural member while free ends of two portions thereof extending in parallel are set to lower ends. With this configuration, the weight of the roof-installed object acts on the lower ends of the two portions extending in parallel in a concentrated manner and the weight of the roof-installed object acts on the roof structural member of a narrow range. This arises a problem that the roof structural member is easy to be damaged.